The basic aim of the proposal is to study unique viral processes in infected cells so that we can eventually design procedures to selectively inhibit them. Two processes are being studied: transcription of messenger RNA from the viral genome and replication of the viral RNA. Both procedures involve RNA-dependent RNA polymerase enzymes, the former present in the viral particles whilst the latter is active in infected cells. The parameters of RNA synthesis by both systems are being currently investigated with vesicular stomatitis and influenza viruses.